When splicing optical fibres mechanically, for example by means of a permanent optical fibre connector, it is generally necessary to prepare the end faces of the fibres to ensure that a satisfactory splice, having low optical losses, is formed.
Co-pending United Kingdom Patent Application No. 0216435.8 (B429) filed by the present applicant discloses an optical fibre connector in which a splice between two optical fibres is formed by means of two ferrules inserted into a connector body, each of which is pre-fixed to a respective optical fibre in a preset orientation with respect to an angled end face of the optical fibre. (By “angled end face” is meant an end face of the optical fibre that is not perpendicular to the longitudinal axis of the fibre.) The ferrules can be inserted into the connector body only in a preset orientation about their axes, and therefore the relative orientations of the two fibre end faces are predetermined to ensure an intimate and low-loss contact between the end faces.
International Patent Application WO 98/54608 discloses a tool for the angled cleaving of optical fibres. The tool cleaves an optical fibre by clamping the fibre under tension by means of two clamping blocks, displacing the fibre between the clamping blocks by means of an anvil so that the displaced part of the fibre experiences a localised shear force, and scoring the fibre. Because the scored part of the fibre is under both tension and shear, the fibre cleaves at an angle away from the perpendicular to the fibre axis. The cleaving tool may be used to cleave an optical fibre that has a ferrule attached to it prior to the insertion of the fibre into the tool. In addition, for polarisation-maintaining (PM) optical fibres, a ferrule that has been pre-attached to such a fibre may be placed in the cleaving tool in a fixed orientation so that the angle of cleave is in the correct orientation with respect to the polarisation axis of the PM optical fibre.